What happens to code that is running on App Platform when there is an update?

Hi there,

When you deploy an update to your app on DigitalOcean’s App Platform, the platform uses a rolling deployment strategy by default. This means it will bring up a new instance of your service with the new code while the old instance is still running. Once the new instance is healthy and ready to serve traffic, the old instance is terminated.

For your use case, there are a couple of things you could consider:

1. Graceful Shutdown:

• App Platform sends a SIGTERM signal to your application when it’s about to shut it down. You can handle this signal in your Flask application to ensure you finish processing any ongoing jobs.
• With Python, you can catch the signal and perform the necessary tasks before shutting down. This way, when your application receives a SIGTERM, it can finish processing the current job and then exit gracefully.

import signal
import sys

def handler(signum, frame):
    print("SIGTERM received. Cleaning up...")
    # Your cleanup code here
    sys.exit(0)

signal.signal(signal.SIGTERM, handler)

2. Job Queue:

• For more advanced job processing, consider using a dedicated job queue system like Redis or Celery. These systems are designed to handle distributed job processing and can manage jobs even when your primary application instances are being restarted or redeployed.
• If a worker gets terminated, most of these systems can re-queue the job to be processed by another worker.

Hope that this helps!

Best,

Bobby